Magnetic properties of nanostructured ferromagnetic FeCuNbB alloys revealed by a novel method for evaluating complex Mössbauer spectra

Abstract

A novel method for analysing complex 57Fe Mössbauer spectra has been successfully applied to nanostructured Fe86-xCu1NbxB13 (x = 5, 7). This method provides an objective model describing the measured spectra. This model consists of the largest meaningful number of lines, given by the `quality' of the measured spectrum, i.e. by the criterion that all line parameters should be well defined. Using this method the temperature dependence of the mean hyperfine fields and the fractions of Fe atoms in different sites of the FeCuNbB samples are derived in the temperature range from 300 K to 700 K. In contrast to conventional methods for determining the hyperfine field distributions in magnetic alloys this approach allows us to evaluate the resulting hyperfine field distributions with indication of their mean-square deviations. The analysis results in detailed information about the iron nanograins, the amorphous residual phase and the so-called interface zone.